An investigation is continuing today into the cause of a crash at Dereham which left a woman driver dead, a male passenger seriously injured and three children in hospital.

The car came off the A47 at Dereham and hit a tree yesterday lunchtime.

The accident happened close to a slip road off the A47.

Police are appealing for witnesses to the crash, which killed the female driver and left a male passenger in a critical condition with a head injury and multiple fractures.

He was being treated at Addenbrooke's Hospital, in Cambridge, while three children, who were seated in the back of the red Citroen estate, were taken to the Norfolk & Norwich University Hospital with minor injuries.

The accident left the Swaffham-bound carriageway of the A47 blocked at the turn-off to the town by the Tesco supermarket for nearly four hours. Traffic was being diverted off the road at the Swanton Morley junction and through the town along Norwich Road.

Traffic queues of about two miles built up from the slip road.

At least four police cars, two fire engines from Dereham, three ambulances and two paramedic cars attended the crash, as well as the air ambulance.

A police spokesman said: 'Officers of Norfolk Constabulary are appealing for witnesses to a single-vehicle road traffic collision just prior to the slip road off the A47 at Dereham at around midday today.

'A car came off the road and collided with a tree. A female who was driving sadly died at the scene.'

Next of kin have been told.

Police spent several hours at the scene carrying out detailed investigations in to what caused the crash.

A spokesman for the fire service confirmed two crews from Dereham had attended and had used hydraulic rescue equipment to cut the casualties out of the car.

The road was reopened just before 4pm.